A01. Describe the Physiological Processes Involved in Stress. (12 Marks)

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SAM If a stressor is percieved as acute by the hypothalamus, its physiological response occurs through the sympathomedullary pathway, made up of the sympathetic adrenal medullary system (SAM) and the sympathetic branch (sympathetic nervous system or SNS). The sympathetic branch (SNS) of the autonomic nervous system (ANS/ self regulating) is activated, the SNS triggers the evolutionary fight or flight response enabling the body to prepare itself in order to deal with the stressor at hand (the flight or flight response is an adaptive response because it maximises our chances of survival under threat). From there the SNS stimulates the production of adrenaline and noradrenaline, needed to “fight” or “flee”, through the adrenal medulla. Some of the physiological results of this production of adrenaline and noradrenaline are pupil dilation allowing the individual to view the threat more clearly (as increased pupil size allows for more light to be let in enabling better vision) and an accelerated heart rate whereby blood can be more rapidly directed to the parts of the body likely to need it like the skeletal muscles as the acceleration allows for a greater blood flow. Other activities are supressed by the fight/flight response so that we maximise diversion of resources to the parts of our body that need it, so for instance bowel movement will decrease and salivation will slow down as it’s not essential that we digest our food (in that moment). HPA If the stressor is percieved as chronic in the high centres of the brain a message passes to the hypothalamus and its physiological response occurs through the pituitary-adrenal system (a.k.a the hypothalamic-pituitary-adrenal axis or HPA). Activation of the HPA, compared to that of SAM, is much less easy to acheive, occuring in response to ongoing stressful situations (chronic) like matters of financial stability. The

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